5 things you must know about run-flat tyres on cars

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kingr
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5 things you must know about run-flat tyres on cars

Post by kingr »

While some insist that the expense is worth it, at least as many motorists regret having bought a car with run-flat tyres. It really depends on personal sentiment, although inconvenience with run-flats - quite apart from their price tag - can be infuriating and debilitating. The argument is often made that if you can’t afford them, you shouldn’t employ them, but an objective appraisal still surmises that run-flats are very expensive, particularly in South Africa, and a potential liability when it comes to repairs.

Displaying the national madness of car prices being comparatively exorbitant in this country, run-flat tyres are also typically three or four times the cost elsewhere in the world, even accommodating rates of exchange. If you’re sitting with a car that has run-flat tyres, or contemplating buying some, there are really five things you should know first.

#1 How do run-flat tyres work?
Using run-flat tyres essentially means you are able to keep on driving safely after a puncture, as they allow you to keep going and find a repair center, within the manufacturer’s specifications on load and distance. You won’t be able to drive indefinitely, even with run-flat tyres, but you can typically maintain town driving for almost 80km before having to repair a run-flat tyre. These tyres allow for continued operation even after the loss of most if not all of the inflation pressure, and do take the immediate panic out of a modest puncture.

In a nutshell, run-flats work according to two typical system specifications. Some types employ a “support ring” of hardened rubber that will carry the car’s weight in the event of a loss of air pressure in the tyre. The other usual construct of a run-flat tyre is that of a self-supporting system, where the tyres have a reinforced sidewall that also continues to support the car’s weight in spite of the tyre’s deflation. The concept has improved tremendously from earlier prototypes over the last two decades or so, and comparisons show that there are legitimate handling abilities and other benefits to fitting run-flat tyres, in spite of their expense and limitations.

Principal among those limitations is that there is no fifth tyre! Run-flat tyres come in sets of four and, although they also come with an in-car kit for inflation under various circumstances, there are some circumstances that can’t be fixed next to the road. This is a potentially huge liability for many motorists, as ripping a tyre wall or doing other more serious damage means you are essentially stuck, waiting for a roll-back to arrive.

#2 How much do run-flat tyres cost?
The short answer is: a lot! Rather, they do cost noticeably more than normal tyres. Although figures of around 15 percent more on average are bandied about by some, mostly those selling them, double the price or more is a far more typical reality. Run-flats take away the option of fitting the most economical yet still-approved tyres available on the South African market, and hence their average price is a lot more for the average motorist, all told. There are no “cheapies” when it comes to run-flats.

With that said, Tiger Wheel & Tyre, for example, is currently posting specials on Pirelli and other run-flats that are pretty reasonably priced. If you’re used to replacing all four tyres when needed for around R5000 or less, however, you’ll have to shift that paradigm upwards - a few notches - if you fit run-flats.

Also, a major consideration and one often hard to verify on the day, is whether the car you’re buying has been fitted with the correct run-flat tyres for the make and model. Although fitment centers seldom get it wrong, other used car industry players often do, and they are no use when it comes to determining whether the sale car you’re eyeing is a huge liability in waiting. If the fitted run-flats are not suitable for the car you’ve bought, you’ll have to incur a wallop of an expense to get it right. Before accepting that higher-tech run-flats imply a high-tech approach, service and repair history, rather spend as much time as you need to confirm that the run-flats fitted on a car you’re about to buy are indeed suitable ones, as per the manufacturer’s dictates.

#3 How are run-flat tyres repaired?

Sealing compound
Run-flat tyres can of course be repaired when needed. Most manufacturers equip run-flat-fitted cars with a sealant kit and compressor in the boot. These items are employed when your tyre is damaged and has a puncture less than 4mm across. These mobility kits are quite easy to use, and their purpose is really simply to inflate your tyre so that you can drive safely to the nearest service center for a repair.

Tyre plug at a service center
Run-flats can seldom be repaired like normal tyres, where you can simply plug a hole for a sound tyre again. Run-flat tyres will need to be removed and repaired by a competent fitment center. Because of their more complicated architecture, a R50 cash puncture repair is forever gone if you’re on run-flats. They need to be repaired properly, and a roadside DIY is seldom going to get you moving again, if you’ve reached the limit of driving on a deflated run-flat. That might sound like no biggie, until you realise that there’s also no spare tyre with a run-flat fitting.

#4 Is there really no spare wheel in the boot?
Yes. With a run-flat fitment, there is no spare tyre! Not having a spare wheel is one of those things that seems almost irrelevant, until you need it. While a driver on run-flats can feel a little smug that they’re driving on safer and better-engineered tyres, all of that evaporates when they’re left stranded next to the road waiting for assistance. If you have a blowout or hit a pothole - an unavoidable national pastime in South Africa - you can’t simply slip on the spare and keep going. Run-flats come in sets of four, without an additional freebie, even a freebie spare wheel with a normal tyre. If you are stranded you will need to call roadside assistance and be towed to a fitment center for assistance.

#5 Can I swap run-flats tyres for normal tyres?
Yes. Mechanically, there are no issues when swapping your existing run-flats with normal tyres, but admin considerations might become onerous. You need to be crystal-clear about any potential insurance issues when swapping into or away from run-flat tyres. It’s best to call your insurer and ask about potential exclusions or any other implications of fitting run-flats before doing it. Your Motorplan might also deny claims if run-flat tyres have been in or out of the equation, depending on whether you bought the car with them fitted or rather retro-fitted them. Here again, it’s best to make sure all of the fine print is still agreeable to you before swapping out tyres.

All in all, run-flat tyres are a huge step up in terms of safety it’s true, but your personal imagining of what happens in the above scenarios will determine whether they are ultimately valuable to you. For most of us, quickly raising several thousand rand in the event of replacement or standing next to the highway without a spare (as has recently happened to Wheel Index team members using run-flats) is an unacceptable upshot of fitting run-flat tyres. With that said, many might as easily find these things manageable, and rather prioritise the safety aspect for their family or themselves. Whatever you decide, make sure you’re aware of all of the implications before tying yourself to a set of run-flat tyres. Far from being simply glorious tech that makes life simpler and safer, they can prove to be a very limiting and persistently expensive purchase.
Kurt #3337

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